Sillimanite gallery

SILLIMANITE Gallery Return to Sillimanite page. Click on image for larger view
Sillimanite is moderately common in the country rocks of the Groton, NH area.
Locality: Draper Hill, Chesterfield, NH	Species: SILLIMANITE Locality: Draper Hill, Chesterfield, NH Specimen Size: 10 cm specimen with prismatic gray-white sillimanite crystals to 1.7 cm Field Collected: Tom Mortimer Catalog No.: 831 Notes:
Locality: Ledge below Palermo #1 Mine, N. Groton, NH	Species: SILLIMANITE Locality: Ledge below Palermo #1 Mine, N. Groton, NH Specimen Size: 9 cm specimen with cream-colored sillimanite crystals to 4.5 cm in biotite schist. Field Collected: Tom Mortimer Catalog No.: 1460 Notes:
Locality: Ledge below Palermo #1 Mine, N. Groton, NH	Species: SILLIMANITE Locality: Ledge below Palermo #1 Mine, N. Groton, NH Specimen Size: Zoom view of specimen 1460 showing splintery structure of sillimanite crystal section. Field of view 1 cm. Field Collected: Tom Mortimer Catalog No.: 1460 Notes:
Locality: Mine road to Valencia Mine, N. Groton, NH	Species: SILLIMANITE Locality: Mine road to Valencia Mine, N. Groton, NH Specimen Size: 3.5 cm specimen with white sillimanite crystal sections to 1.3 cm in biotite schist. Field Collected: Tom Mortimer Catalog No.: 1598 Notes:
Locality: Draper Hill, Chesterfield, NH	Species: SILLIMANITE Locality: Draper Hill, Chesterfield, NH Specimen Size: 6 cm specimen with prismatic gray-white sillimanite crystals to 1.4 cm Field Collected: Walter Caulkin Catalog No.: 806 Notes: This is the specimen I acquired from Walter Caulkin at the June 1990 Gilsum Rock Swap. A short time later, Walter guided me to the Chesterfield, NH source locality.
SILLIMANITE West side of Piper Mtn., Gilford, NH 5 cm specimen with sillimanite crystals in biotite-garnet schist	Species: SILLIMANITE Locality: West side of Piper Mtn., Gilford, NH Specimen Size: 5 cm specimen with sillimanite crystals in biotite-garnet schist Field Collected: Kevin Mortimer - Sept, 2011 Catalog No.: Notes: Likely from Rangely formation. Hardness tested slightly less than 6.
SILLIMANITE Panned from stream on west side of Piper Mtn., Gilford, NH 9 mm sillimanite crystal	Species: SILLIMANITE Locality: Panned from stream on west side of Piper Mtn., Gilford, NH Specimen Size: 9 mm sillimanite crystal Field Collected: Tom Mortimer - Sept, 2011 Catalog No.: Notes: From Rangely formation. Hardness tested slightly less than 6.
SILLIMANITE Rt 11 road cut, near Minge Cove, Alton, NH 3 cm partial sillimanite crystal, (upper middle) in 5.5 cm specimen. Matrix is quartz. SILLIMANITE Rt 11 road cut, near Minge Cove, Alton, NH zoom view of sillimanite crystal.	Species: SILLIMANITE Locality: Rt 11 road cut, near Minge Cove, Alton, NH Specimen Size: 3 cm partial sillimanite crystal, (upper middle) in 5.5 cm specimen. Matrix is quartz. Field Collected: Tom Mortimer (2011) Catalog No.: 1817 Notes: An aluminum silicate mineral was indicated by EDS analysis. Minerals with this chemistry include sillimanite, kyanite, and andalusite. The hardness tested as 7 to 7.5. This, combined with observed silky-fibrous texture in some areas suggests the species is sillimalite. However other zones within the two specimens collected are more bladed and blueish, suggesting kyanite. Deer, Howie & Zussman state in An Introduction to Rock Forming Minerals that "The polymorphic transition of kyanite to sillimanite appears to be sluggish and local persistance of kyanite in the sillimanite zone of metamorphism is not uncommon." The appearance of this crystal suggests that it was undergoing such a polymorphic transition.
SILLIMANITE-KYANITE Rt 11 road cut, near Minge Cove, Alton, NH 8 cm specimen with with kyanite-sillimanite crystal zoning. Matrix is biotite gneiss. SILLIMANITE Rt 11 road cut, near Minge Cove, Alton, NH Zoom view of bottom side shows gray, un-altered sillimanite, top left, blueish kyanite (unfocused) to right. (Green is organic)	Species: SILLIMANITE-KYANITE Locality: Rt 11 road cut, near Minge Cove, Alton, NH Specimen Size: 8 cm specimen with with kyanite-sillimanite crystal zoning. Matrix is biotite gneiss. Field Collected: Tom Mortimer (2011) Catalog No.: 1818 Notes: Zoom view of bottom side shows gray, un-altered sillimanite, top left, blueish kyanite to right. These Alton specimens are the only examples the author has seen of New Hampshire sillimanite-kyanite zoned crystals.